Breath odor is the scent of the air you breathe out of your mouth. Unpleasant, distinctive, or offensive breath odor is commonly called bad breath.

Bad breath; Halitosis

Some disorders will produce specific, characteristic odors to the breath.

Bad breath related to poor oral hygiene is most common and caused by release of sulphur compounds by bacteria in the mouth.

A fruity odor to the breath occurs as the body attempts to get rid of excess acetone through the breathing. This is a sign of ketoacidosis, which may occur in diabetes. It is a potentially life-threatening condition.

Breath that smells like feces can occur with prolonged vomiting, especially when there is a bowel obstruction. It may also occur temporarily if a person has a tube placed through the nose or mouth to the stomach to drain the stomach contents (nasogastric tube) in place.

The breath may have an ammonia-like odor (also described as urine-like or "fishy") in people with chronic kidney failure.

If previously normal breath turns into halitosis, causes could include:

• Abscessed tooth
• Alcoholism
• Cavities
• Dentures
• Drugs
  • Paraldehyde
  • Triamterene and inhaled anesthetics
  • Insulin - injection
• Food or beverages consumed (such as cabbage, garlic, raw onions, or coffee)
• Foreign body in the nose (usually in children)
  • Often (but not always) there is a white, yellowish, or bloody discharge from one nostril
• Gum disease (gingivitis, gingivostomatitis)
• Impacted tooth
• Lung infection
• Poor dental hygiene
• Sinusitis
• Throat infection
• Tobacco smoking
• Vitamin supplements (especially in large doses)

Diseases that may be associated with breath odor (not presented in order of likelihood -- some are extremely unlikely):

• Acute necrotizing ulcerative gingivitis
• Acute necrotizing ulcerative mucositis
• Acute renal failure
• Bowel obstruction (can cause breath to smell like feces)
• Bronchiectasis
• Chronic renal failure (can cause breath to smell like ammonia)
• Diabetes (fruity or sweet chemical smell with ketoacidosis)
• Esophageal cancer
• Gastric carcinoma
• Gastrojejunocolic fistula (fruity-smelling breath)
• Hepatic encephalopathy
• Diabetic ketoacidosis
• Lung abscess
• Ozena, or atrophic rhinitis
• Periodontal disease
• Pharyngitis
• Zenker's diverticulum

Review Date: 02/22/2010
Reviewed By: Jack D Rosenberg, DDS, Advanced Dental Care, Palm Beach Gardens, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, M.D., MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)